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CO oxidation on Pt: Variable phasing of inputs during forced composition cycling
Author(s) -
Graham William R. C.,
Lynch David T.
Publication year - 1990
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690361203
Subject(s) - cycling , chemistry , thermodynamics , volumetric flow rate , adsorption , gas composition , platinum , analytical chemistry (journal) , materials science , mechanics , catalysis , chromatography , physics , archaeology , history , biochemistry
A combined experimental and theoretical investigation of the effect of forced feed composition cycling for CO oxidation on platinum has been performed. A novel approach to forced composition cycling was examined, in which the phase angle between the two input streams was varied. Reaction rate enhancement is shown to occur, and by varying the phasing of the feed streams it is possible to achieve a global maximum in the time‐average reaction rate. This phenomenon can be explained quantitatively by a model based on an adsorbate‐induced phase change of the Pt surface combined with CO adsorption self‐exclusion. This mathematical model can also quantitatively describe the complex steady‐state behavior (uniqueness‐multiplicity transitions) observed for this reaction. The predictions of the model have been validated further through a detailed experimental study of the effects of feed flow rate, temperature, size of catalyst charge, and cycling frequency on the instantaneous and time‐average conversions during forced cycling of the feed composition.